Safe Use of
Cylinder Gases
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Introduction
 Compressed gases used in a variety of industrial and
laboratory situations
 Compressed gases present a unique hazard. Depending on
the particular gas, there is a potential for simultaneous
exposure to both mechanical and chemical hazards
 Gases can be:
– Flammable or combustible
– Explosive
– Corrosive
– Poisonous/toxic
– Inert
– Cryogenic
– Pyrophoric(burns on contact with air)
– or a combination of hazards
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Introduction
Common Industrial Gases
 Oxidants support combustion e.g. air & oxygen
 Inerts do not generally react with other materials,
asphyxiants(leak displace air) e.g. nitrogen, argon,
helium
 Flammables when mixed with oxidant and ignition
source will burn e.g. acetylene, hydrogen, propane
 Toxics toxic in small concentrations e.g. ammonia,
chlorine, carbon dioxide
 Corrosives react with materials causing reactions
e.g. chlorine, sulfur dioxide
 Pyrophorics ignite spontaneously in air e.g. silane,
phosphine
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Main Causes of Accidents
 Inadequate training and supervision
 Poor installation
 Poor maintenance
 Faulty equipment and/or design(e.g badly
fitting valves or regulators)
 Poor handling
 Poor storage
 Inadequately ventilated working conditions
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Main Hazards
 Impact from the blast of a gas cylinder
explosion or rapid relase of compressed gas
 Impact from parts of gas cylinders that fail
or any flying debris
 Contact with the released gas or fluid(such
as chlorine)
 Fire resulting from the escape of flammable
gas or fluids such as LPG
 Impact from falling cylinder
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Safe Working with Gas Cylinders:
Identification and Properties
 Read the label to see what gas you are dealing with and double
check tha the cylinder/gas is right for th eintended use
 No compressed gas cylinder should be accepted for use that
does not legibly identify its contents by name
 If the labeling on a cylinder becomes unclear or an attached tag
is defaced to the point the contents cannot be identified, the
cylinder should be marked "contents unknown" and returned
directly to the manufacturer
 Never rely on the color of the cylinder for identification. Color
coding is not reliable because cylinder colors may vary with the
supplier. Additionally, labels on caps have little value because
caps are interchangeable
 If there is a mismatch between the color of a cylinder and the
label. Do not use, contact the supplier immediately
 Know the properties of the gas (read Material Safety Data Sheets
available from your Supervisor)
 The cylinder’s contents should be identified at all times as well
as the cylinder status (full, empty or in service)
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Safe Working with Gas Cylinders
Work Practices
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Securely restrain cylinders to prevent them falling over
Close the cylinder valve and replace dust caps when cylinder not in use
Before connecting a gas cylinder to equipment or pipework make sure regulator and
pipework are suitable for the gas and pressure being used
Never drop a gas cylinder
Never tamper with cylinders or subject them to abnormal mechanical shocks which
could damage the valve or safety device
Never re-paint, change markings or identification or interfere with threads
Never disguise damage to a cylinder or valve. Label as faulty and contact the supplier
Never attempt to repair a cylinder
Never scrap a cylinder
Never subject cylinders to abnormally high or low temperatures
Never mix gases in a cylinder
Never try to refill a cylinder unless properly trained to do so
Never transport by rolling them on the ground or use them as rollers or supports
Never pick them up by magnetic lifting
Never subject to abnormal mechanical shocks whuch could damage the valve or safety
device
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Safe Working with Gas Cylinders
Daily Inspection
Cylinders should be inspected daily
and prior to each use for corrosion,
leaks, cracks, etc.
Inspection should include the
cylinder, piping, safety relief
devices, valves, protection caps and
stems.
Leaking regulators, cylinder valves
or other equipment should be taken
out of service.
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Safe Working with Gas Cylinders
 Maintenance of cylinders and their valves or relief devices shall be
performed only by trained personnel.
 An emergency response plan shall be developed and implemented
wherever compressed gas cylinders are used, handled or stored.
 Never smoke around compressed gas cylinders.
 Valve protection caps must remain in place at all times except when
cylinders are secured and connected to dispensing equipment
 Only wrenches or tools provided by the cylinder supplier should be
used to open or close a valve. At no time should pliers be used to
open a cylinder valve.
 Never apply PTFE tape, jointing compounds or any other sealing
material to the valve in an attempt to achieve a tight seal, if a gas
tight seal cannot be achieved metal to metal, replace the regulator or
change the cylinder
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Gas Cylinder Use
After the regulator is attached, the cylinder
valve should be opened just enough to
indicate pressure on the regulator gauge (no
more than one full turn) and all the
connections checked with a soap solution for
leaks.
Never use oil or grease on the regulator of a
cylinder valve.
Before a regulator is removed from a cylinder, the cylinder valve shall
be closed and the regulator relieved of gas pressure.The valve
cap shall be replaced, the cylinder clearly marked as "empty,"
and returned to a storage area for pickup by the supplier
Regulators, gauges, hoses and other apparatus shall not be used on
gas cylinders having different chemical properties
Valve outlet thread size is different for different products but the
same products from different gas suppliers will have the same
thread
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Gas Cylinder Regulators
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A regulator is a device that receives gas at a high
pressure and reduces it to a much lower working
pressure
Precision instruments and MUST be handled with care
to avoid damage to their sensitive springs, diaphragms,
valve seals etc.
Equipment should display the relevant
European/British Standard number and the pressures
up to which it can operate
Leave the pressure adjustment knob/screw fully out
when the regulator is not in use (this ensures a
minimum of tension on the springs and diaphragms)
Cylinders should be placed with the valve accessible at
all times. The main cylinder valve should be closed as
soon as it is no longer necessary that it be open, it
should never be left open when the equipment is
unattended or not operating
This is necessary not only for safety when the cylinder is
under pressure, but also to prevent the corrosion and
contamination resulting from diffusion of air and
moisture into the cylinder after it has been emptied.
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Flashback Arrestors
 Flashback is the result of mixture of fuel gas and oxygen
burning within the hose, flame travels and burns its way
towards the gas source at great speed, can result in force of
explosion in either cylinder
 Flashback arrestors must be fitted on both oxygen and fuel
gas regulators
 If flashback arrestor is dropped/damaged replace
immediately
 Flashback arrestors should oinly be used with the gas they
are labelled for and the presuure thay are designed for
 Comon reasons for flashback: incorrect purging of hose/torch
prior to use, incorrect gas pressure, incorrect nozzle,
damaged torch valves, gas passages blocked within the torch,
kinked or trapped hose
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Hoses
 Correct hose bore size, pressure rating, length and color coding are essential
for safety BS EN 559
 Blue – oxygen, Red - acetylene and other fuel gases(except LPG)
 Black – inert and non combustible gases
 Orange – Liquified Petroleum Gas
 Never use hoses that are longer than necessary
 Never use equipment while hoses are wrapped around the cylinders or trolley
 Length of hose should be suitable for the task
 Keep hoses in good condition
 Examine the hose for cracks, deterioration, damage and test the hose for
leaks before use
 Do not repair hoses unless you have the skill and means to test hem in
accordance with BS En 1256
 Purge hose thoroughly before lighting torch
 Do not put wrapping tape around hosing as this contains combustible
hydrocarbons
 Do not use copper piping with acetylene hoses as it is potentially explosive
 Protect hosing from heat, oil, grease or mechanical damage
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Piping
 Distribution lines and their outlets should be
clearly labeled as to the type of gas contained
 Piping systems should be inspected for leaks on a
regular basis
 Special attention should be given to fittings as well
as possible cracks that may have developed
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Blow Pipes and Torches
 Leaks are a serious hazard as they are closest to the operator
 Always check condition before use, ensure tip is free of obstruction
 Signs of heat damage around the blow pipe or torch may indicate the equipemnt
has sufferd interal damage and is leaking and should be replaced immeidately
 No sign of sideways movement of the cutting leaver as this could cause gas
leaks within the body of the torch that are difficult to detect
 Always fit the correct size nozzle for the job( hole size and pressure set at
regulator determine gas flow and gas velocity exiting the nozzle, manufacturer
gives a pressure rating for the nozzle being use, if the gas exit velocity is slower
than the combustion velocity backfire and flashback may occur
 Replace blow pipe or torch if
 Broken bent or loose gas control valve
 Bent mixer, misshapen cutter head
 Bent cutter tube
 Broken of bent cutting oxygen lever
 Leak test all connections and valves prior to use
 If replacing O ring seals always use the correct materials
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Acetylene
Unique properties
 Acetylene gas under excess pressure becomes
unstable
 Cylinders should never be subject to intense heat
or physical impact as the rise in temperature and
pressure may cause the acetylene to thermally
decompose
 Prior to moving a cylinder that has been subject to
heat or severe impact contact trained emergency
personnel who can check for temperature rise and
apply correct procedures
 The cylinder may appear normal but if it is moved
it may detonate with fatal consequences
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Handling Gas Cylinders
 Wear PPE: gloves, protective footwear, eye protection
 Correct way to move cylinders is to: keep upright, secure and with
valves uppermost
 Use mechanical aids such as a trolley where reasonably practicable(
do a risk assessment)
 Use suitable cradles, slings, clamps or other effective means when
lifting with a hoist or crane
 For short distances on even ground the practice of ‘milk-churning’
(manually moving cylindres) can be used only by trained personnel
and never for longer distances, in uneven ground, wet or icy
conditions, poor lighting, or at speed a trolley should be used
 All personnel involved should have completed manual handling
training
 Never roll cylinders along the ground
 Never transport cylinder with valve and pressure regulator attached
or with the valve open
 Never attempt to catch a falling cylinder just get out of the way
 Never lift a cylinder by its cap, valve or guard/shroud
Remember that a cylinder is never empty
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Transporting Cylinders
Carriage of Dangerous Goods Regulations apply
 If possible carry in open vehicles or trailers
 If they must be carried in closed vans/cars ensure good
ventilation at all times
 If the load compartment is not separated from the driver
do not carry toxic gas cylinders (those with a toxic gas
label and having yellow as a colour on the cylinder)
 Secure cylinders properly so they cannot move or fall in
transit or do not project beyond the edges of the vehicle,
normally in the upright position unless instructions for
transport state otherwise
 Ensure gas cylinders are clearly labelled to show contents
and associated hazards
 Fit suitable protective valve caps and covers to cylinders
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Transporting Cylinders
Carriage of Dangerous Goods Regulations apply
 Disconnect hoses and regulators from cylinders
 Carry propane cylinders upright and do not
carry flammable gas cylinders in the same
compartment as toxic gas cylinders
 Do not smoke while carrying cylinders inside
vans/cars
 Unload the cylinders as soon as possible and
move to a well ventilated storage area
 If you suspect it is leaking, park the vehicle,
investigate the fault and contact the supplier
 If you are involved in an accident advise, any
emergency services involved what gas cylinders
are being carried
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Safe Storage
Each Storage area should be subject to unique risk assessment
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It is best to store gas cylinders in the open and on concrete in a fenced
compound with some weather protection
In storage areas oxygen cylinders must be stored at least 3 metres
away/separated by a fire wall from fuel gases such as acetylene,
propane, methane etc.
Full cylinders should be stored separately from empties and empty
oxygen cylinders should be segregated from empty fuel gas cylinders
Other products should not be stored in the gas storage areas
especially not oil or corrosive liquids, sources of ignition or flammable
materials
Ease of access into and around storage area, such as provision of aisle
>0.6m to prevent domino effect
LPG cylinders have special requirements including storage 3m away
from other gases
Pyrophoric and toxic gases should be stored seperately in locked,
suitable ventilated storage areas with restricted access
Protect gas cylinders from external heat sources which may adversely
affect their mechanical integrity
Cylinders should be secured and properly restrained, secure with
straps or chains connected to a wall bracket or other fixed surface, or
by use of a cylinder stand
Cylinders should be clearly labelled to show contents and associated
hazards
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Safe Storage
 Store all cylinders upright and secure on a level surface to
prevent them from falling
 Acetylene and propane must never be stacked horizontally
either in storage or in use
 Storage arrangements should ensure turnaround of stock in
adequate time
 Storage areas with gas cylinders must have more than one exit
 Cylinders should be located away from any heat/source of
ignition and if possible away from the fire exits, elevators,
walkways, building egresses, unprotected platform edges, or in
locations where heavy moving objects may strike or fall on them
 Storage arrangements should be clearly described in the
emergency plan
 Storage area must have good housekeeping and adequate
warning signs with fire fighting equipment as necessary
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Cylinder Incident Response
Report any damaged/leaking cylinder to supplier
If a cylinder is leaking but the leak has not ignited and it
is safe to do so having considered the gases specific
properties:
 Eliminate all sources of ignition
 Ensure the valve is closed but do not over-tighten it
 Put the cylinder in a safe place that is well-ventilated –
keep it upright
 Mark the cylinder as faulty and not to be used
 Warn everyone in the area of the gas leak
 Inform the supplier
 Ensure the work area is thoroughly ventilated before
continuing with any work
 If a hydrogen cylinder is involved be aware that
hydrogen burns with an invisible flame so seek expert
assistance
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Cylinder Incident Response
Report any damaged/leaking cylinder to supplier
If a cylinder is leaking and it has ignited it could
explode
Call the emergency services and evacuate the
area to a minimum distance of 100 metres
Where a cylinder has been damaged
 If it has been dropped or physically damaged check it
for leakage and deal with as for a leaking cylinder
 For handling acetylene cylinders should not be moved
unless it is clearly established that there is no
thermal disassociation
 Clearly mark any cylinder that has been exposed to
excessive heat or physical impact and contact the
supplier
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Cylinder Incident Response
If a flashback has occurred:
 Close both blowpipe valves oxygen first
 Close both cylinder valves
 Check the temperature of the acetylene cylinder for
thermal decomposition
 Check the blowpipe has not overheated
 Check the nozzle is not damaged
 Open both blowpipe valves oxygen first to vent the
system
 Unwind the pressure adjustment screw on each
pressure regulator
 Before starting up again, check the integrity of the
whole system
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Cylinder Incident Response
Gas Cylinders on Fire
Depends on the gas, whether the gas is alight at the cylinder
valve or if the cylinder has been subject to severe pressure as
a result of the heat from the fire. Nature of hazard will
determine procedure to be applied
 If cylinder has been involved in fire do not approach, evacuate
the area to 100m minimium to 300m
 Call fire brigade
 Use large quantities of water to cool the cylinders if safe to do so
(do not aim high pressure water direct at the cylinders) from a
safe location and await the arrival of trained emergency
personnel (Emergency plan training should address)
 Remove any cylinders not involved in fire to safe place, ensure
valves are closed if safe to do so
 Inform gas supplier,
 If cylinder contents are unknown, treat as acetylene
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In Your Workplace
Look Out for Gas Cylinders:
In horizontol position/on the ground
In contact with electrical cords
Not protected from falling – chain not secure
Damaged
In an area where could be subject to impact such
as near operating forklift
 Stored near combustibles
 Oxygen and acetylene stored together
 Without valve caps
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Deal with these Hazards IMMEDIATELY
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Conclusions
 Compressed gases present a unique hazard. Depending on
the particular gas, there is a potential for simultaneous
exposure to both mechanical and chemical hazards
 Inadequate training and supervision, poor installation, poor
maintenance, faulty equipment and/or design(e.g badly
fitting valves or regulators), poor handling, poor storage,
inadequately ventilated working conditions
 When working with compressed gases you need to know the
properties of the gas, safe use procedures and what to do
when things go wrong
 For detailed use of individual gases you should now review
the relevant Material Safety data Sheet (MSDS) for each gas
used on your site
Always Treat Gas Cylinders with Respect
For additional information which could be used as presentation handouts visit UK
HSE information on Gas Safety for a whole series of leaflets on the topic
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